Previous research has suggested that the choice between public transport and private car use is not solely based on utility considerations, such as time and cost. However, affective considerations tend not to be targeted in policy interventions to reduce car use. This may be due, in part, to a lack of clarity about which affective responses to car use are important and how they may affect willingness to switch to public transport. This study sought to clarify the role of affective responses in transport mode choice. An interpretative phenomenological analysis (IPA) of car users' accounts was conducted to (i) explore affect associated with decisions to drive or use public transport to get to work; and (ii) describe the role of affect on such transport decisions, and its relationship to utility considerations. Semi-structured interviews were conducted with 18 car users employed at a medium-sized UK university. Four affect themes were identified: These were journey-based affect (JBA), personal space, autonomy and identity. Typical 'utility' factors such as time, cost and reliability had important affective effects, and these were considered alongside utility components (e.g. getting to work on time). However, these effects were not always additive, and the role of affect depended on participants' own assessment of their circumstances. Implications for interventions are discussed.